Mask



FIG. 1 is a front view a mask;

FIG. 2 is a right side view of the mask shown in FIG. 1, with the left side view being a mirror image thereof;

FIG. 3 is a top view of the mask shown in FIG. 1;

FIG. 4 is rear view of the mask shown in FIG. 1;

FIG. 5 is an isometric view of the mask shown in FIG. 1; and,

FIG. 6 is a bottom view of the mask shown in FIG. 1.

The broken lines in the drawings depict portions of the mask that form no part of the claimed design. 

CLAIM The ornamental design for a mask, as shown and described. 